ProTec success in China with LFT pultrusion lines

Suzhou Sunway Polymer from the city of Suzhou in Jiangsu Province is a Chinese customers and is now producing pellets using its two ProTec LFT pultrusion lines.

In 2017, the compounder purchased its first 32 strand LFT pultrusion line from ProTec which has a pellet production capacity of 500kg/h, while a second unit with 64 strands and twice the output followed in 2019. Over the last year, the company also ordered two SOMOS Gramix S9 gravimetric dosing and mixing systems which will be brought into service on the lines this year.

Pultrusion, derived from “pull” and “extrusion”, can be used to produce a wide range of fibre reinforced plastics. ProTec’s pultrusion lines allow plastics manufacturers to automate the high-efficiency production of LFT pellets. The fibre-polymer combination can include virtually any common thermoplastic with reinforcement being provided as required by glass, steel, aramid or carbon fibres. The LFT pellets are injection moulded into lightweight, high-strength components with very good surface quality for use in automotive construction, in the electrical, packaging and sporting article industries and in aerospace.

Suzhou Sunway Polymer, founded in 1998, supplies Chinese Tier 1 automotive industry suppliers who in turn manufacture exterior and interior components for domestic, US, Japanese and German automotive manufacturers. Annual output of resin compounds is some 100,000 tons, generating turnover of around EUR 150 million in 2018. The compounder relies on European and Japanese suppliers for both its manufacturing and its measuring and testing technology.

Sunway extends product range with LFT pellets

Sunway’s production manager Chang Chun You and product developer Qi Bang Huang were first made aware of ProTec by one of the German supplier’s LFT pultrusion lines on another user’s premises in the region. They recognised an opportunity for Sunway also to position itself on the market for the efficient production of long fibre reinforced thermoplastics. The company wants to expand its range, as product developer Qi Bang Huang explains: “Our aim is always to offer Sunway’s automotive customers innovative products and solutions and so generate quality and cost benefits.” In the medium term, the company also aims to expand its market to include Europe.

Production manager Chang Chun You was also convinced by ProTec’s reference line: “Its quality, reliability and efficiency thrilled me.” Fei Peng, general manager at ProTec Polymer Processing in Shanghai, was the main contact and assisted with application-specific configuration of the Sunway lines: “ProTec is a one-stop-shop for planning, construction and commissioning because, in addition to LFT pultrusion lines, we can offer components, solutions and turnkey systems for the entire materials handling process including dosing, drying and conveying.”

High-speed retrofit: productivity up, costs down

Sunway is one of the first companies to express an interest in the new high-speed retrofit for ProTec’s pultrusion lines. Involving only few modifications, the retrofit raises an existing line’s production speed from 30m/min to 50m/min. As a result, output of high-quality LFT pellets is increased by up to two thirds and production costs are correspondingly reduced. This innovation is ProTec’s response, as a systems supplier to the international plastics industry, to rising Chinese demand for its lines. The retrofit was initially set to be the centrepiece of ProTec’s presence at the now cancelled Chinaplas show.

Producing more LFT pellets faster

The new high-speed retrofit requires only slight modifications and additions to be made to existing pultrusion lines. Modifications include the addition of a preheater and optimisation of die geometry. As a result, the fibres can be adjusted to temperature more quickly, so ensuring faultless impregnation at a distinctly higher production rate. A second water bath also increases cooling capacity. ProTec has likewise modified the pelletiser. In the high-speed variant, specially arranged rotary knives chop the pellets at high speed to the optimum processing length of 6-12mm.

New applications

ProTec is also currently developing further innovative applications which can be produced using its LFT pultrusion lines, including technology for producing long fibre reinforced thermoplastic profiles usable for example as reinforcing elements in the building industry. ProTec is also working on particularly robust impregnated fibre strands which can be used for reinforcing injection mouldings in the automotive and aerospace industries.